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Today is the 400th Anniversary of Galileo Discovering Ganymede
On Jan 19, 9:13*pm, Bill Owen wrote:
Eric Chomko wrote: The most interesting use of the Jovian moons was Roemer trying to guess the speed of light.http://en.wikipedia.org/wiki/R%C3%B8...on_of_the_spee... Or the timing of eclipses as a method of determining longitude. *Jay Lieske, before his retirement from JPL, found a veritable treasure trove of 17th and 18th century eclipse observations, which helped constrain the mean motion of the satellites before Galileo (the spacecraft) did it far better. After the antenna glitch on Galileo it is encouraging to read about something it did well. http://adsabs.harvard.edu/abs/1986A%...6AS...63..143L -- Bill Owen |
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Today is the 400th Anniversary of Galileo Discovering Ganymede
Eric Chomko wrote:
On Jan 19, 9:13 pm, Bill Owen wrote: Eric Chomko wrote: The most interesting use of the Jovian moons was Roemer trying to guess the speed of light.http://en.wikipedia.org/wiki/R%C3%B8...on_of_the_spee... Or the timing of eclipses as a method of determining longitude. Jay Lieske, before his retirement from JPL, found a veritable treasure trove of 17th and 18th century eclipse observations, which helped constrain the mean motion of the satellites before Galileo (the spacecraft) did it far better. After the antenna glitch on Galileo it is encouraging to read about something it did well. http://adsabs.harvard.edu/abs/1986A%...6AS...63..143L -- Bill Owen Thanks, Eric. The four Galileans are massive enough that their gravitational signature showed up easily in the Doppler pretty much all the time we were in orbit -- not just during flybys -- this meant that the radio tracking data served so well to pin down Galileo's trajectory that we could forgo optical navigation imaging after the first five or six revolutions. Galileo managed to get a lot done very well, despite the antenna glitch and the resulting huge hit to the data volume. The satellite science was just fine, the fields and particles stuff was OK -- the big loser was atmospheric science, which was heavy on imaging. They got a lot of that back during Cassini's flyby, and presumably even more from New Horizons. -- Bill |
#23
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Today is the 400th Anniversary of Galileo Discovering Ganymede
Bill Owen wrote:
Galileo managed to get a lot done very well, despite the antenna glitch and the resulting huge hit to the data volume. The satellite science was just fine, the fields and particles stuff was OK -- the big loser was atmospheric science, which was heavy on imaging. They got a lot of that back during Cassini's flyby, and presumably even more from New Horizons. Toward the end of its mission Galileo got great close-up shots of Io's volcanoes where you could see the lava glowing down inside the craters; http://zuserver2.star.ucl.ac.uk/~idh/apod/ap020327.html http://www-aig.jpl.nasa.gov/public/p...io_volcano.jpg Did they ever figure out why the drop probe gave such unexpected results during its descent into the clouds? Did it come down in a boundary between two cloud belts as was speculated at the time? Pat |
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